1. Field of the Invention
The invention relates to a looper for measuring the wedge proportion of a longitudinal pull present within a strip in the longitudinal direction of the strip, wherein the wedge proportion extends across the strip width.
2. Description of the Related Art
A looper is known from the publication xe2x80x9cDevelopment of new high performance loopers for hot strip millsxe2x80x9d, Iron and Steel Engineer, June 1997, pp. 64 to 70, which comprises two dynamometers for measuring a force exerted onto the looper which corresponds to the longitudinal pull. Nothing is disclosed in this article in regard to the arrangement of the dynamometers and the general configuration of the looper.
From German patent document 197 15 523 A1 a measuring device for determining flatness is known which has a plurality of measuring rolls. The measuring rolls are individually supported on pivot arms which are connected to a looper shaft. By rotating the looper shaft the measuring rolls can be adjusted relative to the strip. The pivot arms are divided by joints into a shaft portion and a roll portion wherein the joints deflect restoring forces, exerted by the strip onto the measuring rolls and corresponding to the longitudinal pull, onto the dynamometers arranged on the respective pivot arm.
It is an object of the present invention to provide a looper having a simple configuration with which the wedge proportion, extending across the strip width, of the longitudinal pull can be measured.
In accordance with the present invention, this is achieved in that:
the looper has a continuous looper roll extending across the strip width and being supported on both sides on a pivot arm, respectively;
the pivot arms are connected with a looper shaft;
when rotating the looper shaft the looper roll can be adjusted relative to the strip;
the pivot arms are divided by a joint into a looper shaft arm and a looper roll arm;
each joint deflects a restoring force, exerted by the strip onto the looper roll and corresponding to the longitudinal pull, onto the dynamometer arranged on the pivot arm, respectively.
When the looper roll arm is formed as a plate or as a lever frame, the looper is of an even more simplified construction.
When the looper shaft arm and the looper roll arm are connected to one another in the proximity of the dynamometer via a securing element, it is reliably prevented that the looper roll arm can lift of the dynamometer.
When the joint, the looper roll, and the dynamometer define a triangle with three sides and the securing element is arranged outside of this triangle, the securing element is exposed to comparatively low forces.
When the triangle is formed as a substantially isosceles triangle, a low mechanical loading of the looper roll arm results.
The loading of the looper roll arm can be further minimized when the triangle is formed as a substantially rectangular (right) triangle.
When one of the sides of the triangle is positioned opposite the joint and this side is longer than the two other sides of the triangle, the forces exerted onto the looper roll arm are particularly minimal.
When the looper shaft arm is at least as long as the looper roll arm, the looper is provided with a large adjusting range.
The mechanical loading is minimized when the dynamometer has a force axis and the looper roll arm performs a movement in the area of the dynamometer which is essentially parallel to the force axis.